1. Technical Field
The present invention relates to optical imaging devices and, particularly, to a lens with a collar and a lens module using the same.
2. Description of Related Art
With the development of optical imaging technology, electronic devices, such as digital cameras and mobile phones to name a few, adopting imaging technology has been introduced and marketed.
A typical lens module 40 is shown in FIG. 6. The lens module 40 includes a barrel 42, a first lens 44, a second lens 46, and a spacer 48 received in the barrel 42. The spacer 48 is sandwiched between the first lens 44 and the second lens 46. The first lens 44 includes an active part 442 and an inactive part 444 surrounding the active part 142. The active part 442 is configured for refracting light transmitting therethrough. The inactive part 444 has a first flat surface (not labeled). Similarly, the second lens 46 includes an active part 462 and an inactive part 464. The inactive part 464 has a second flat surface (not labeled). A first side of the spacer 48 contacts the first flat surface of the inactive part 444, and an opposite second side of the spacer 48 contacts the second flat surface of the inactive part 464. In assembly, the first lens 44, the spacer 48, and the second lens 46 are in this order placed into the barrel 42.
In the above lens module 40, the second lens 46 is engaged with the first lens 44 via the spacer 48. Due to accumulated errors during assembly of the spacer 48 and the second lens 46, an optical axis (not labeled) of the second lens 46 may deviate from that of the first lens 44. Accordingly, imaging quality of such a lens module 10 deteriorates, directly depending on the deviation between the two optical axes.
Therefore, a new lens and a new lens module are desired to overcome the above mentioned problems.